It is widely recognized that maintaining correct inflation pressure in vehicle tyres results in increased fuel efficiency and increased safety. Fuel efficiency is enhanced when a properly filled tyre maintains a tyre manufacturer's recommended contact patch with a drive surface, thereby decreasing rolling resistance. Under- and over-inflated tyres are likely to fail as a result of stresses on tyre components, blowouts, or other causes and, consequently, can present a significant hazard risk for an operating vehicle. When the recommended pressure for a tyre is maintained, the likelihood of such risks should be minimized. Like some other vehicle tyres, aircraft tyres are designed to carry specified loads through a range of temperatures and wheel speeds. Unlike the tyres of vehicles that travel solely on ground surfaces, however, aircraft tyres must withstand external pressure at different altitudes and the forces associated with landing and takeoff, as well as travel conditions on ground surfaces. Aircraft tyres have long been required to be filled with nitrogen gas, which both reduces fire risks and extends tyre useful life. Even when aircraft tyres are filled with nitrogen, however, maintaining correct pressure in aircraft tyres is a key factor in ensuring that aircraft tyres and the landing gear wheel assemblies supporting them perform safely and reliably under the high static and dynamic loads encountered during landing, taxi, and takeoff. Taking steps to ensure that correct tyre pressure is maintained is of the utmost importance for safe aircraft ground movement, as well as for safe takeoff and landing operations.
It has been proposed to drive aircraft independently during taxi using motors and other drive means to move one or more drive wheels and move aircraft during ground movement. U.S. Pat. No. 7,445,178 to McCoskey et al, for example, describes electric nose wheel motors intended to drive aircraft during taxi. U.S. Pat. Nos. 7,469,858 to Edelson; 7,7,891,609 to Cox; U.S. Pat. No. 7,975,960 to Cox; U.S. Pat. No. 8,109,463 to Cox et al; and British Patent No. 2457144, owned in common with the present invention, describe electric drive motors and systems e to power aircraft wheels and move an aircraft on the ground without reliance on aircraft main engines or external tow vehicles. While the drive motors described in these patents can effectively move an aircraft autonomously without aircraft engines during ground operations, there is no suggestion of a relationship between efficient autonomous aircraft taxi and aircraft tyre pressure.
When aircraft are equipped with one or more landing gear wheels powered by landing gear wheel drive assemblies to move the aircraft on the ground autonomously without using the aircraft's main engines or external tow vehicles, operation of the components of a landing gear wheel drive assembly may have at least some effect on tyre pressure and that tyre inflation pressure may also have some effect on landing gear drive assembly operation. These relationships are not acknowledged or suggested by the prior art.